1. Field of the Invention
The present invention relates to a treatment device.
2. Description of the Related Art
There is known a forceps that grasps a biological tissue or the like as a treatment target in, for example, endoscopic surgery using a laparoscope. In endoscopic surgery, the forceps strongly grips a metallic clip on a grip section proximal end side in some situations. Moreover, at a proximal end of the grip section closer to a fulcrum point than at a distal end of the same, a gripping force increases more owing to a leverage ratio.
Further, there is also known an ultrasonic treatment device that grips a biological tissue by use of a grip member and a probe that transmits ultrasonic vibration and coagulates or incises the gripped biological tissue by ultrasonic vibration of the probe. For example, Jpn. Pat. Appln. KOKAI Publication No. 11-113922 discloses an example of such an ultrasonic treatment device. A velocity distribution of ultrasonic vibration in the probe is maximum at a distal end, and it is zero at a position corresponding to a ¼ wavelength from the distal end. A vibration velocity at a proximal end of the probe is smaller than a vibration velocity at a distal end of the probe. Therefore, a capability to coagulate or incise a biological tissue is poorer at the proximal end portion than at the distal end of the probe. Therefore, Jpn. Pat. Appln. KOKAI Publication No. 2005-288024 discloses a technique of increasing a gripping force at a proximal end portion of a probe to improve a capability to coagulate or incise a biological tissue at the proximal end portion of the probe. Furthermore, Jpn. Pat. Appln. KOKAI Publication No. 11-113922 discloses a technique of making a value of a section modulus of a probe at a proximal end portion higher than that at a distal end portion, to improve strength of the probe.